rules since 1986.
Recently, GL was commissioned
by the five European shipyards in-
volved in the development of the E3
double-hulled tanker to calculate
and assess the collision resistance of
this vessel. The 280,000-dwt ship
has a capacity of two million barrels
and is designed to fulfill all of today's
environmental regulations, as well
as those expected in the future. The
assessment of collision resistance
was based on a collision between
two moving vessels of the same size,
and between a moving vessel and a
stationary vessel, with variation in
the draft of both vessels. Two differ-
ent bow shapes for the striking ves-
sel were investigated: a bulbous bow
and a raked bow (see Figure 1).
GL is also breaking ground in the
technology of surveying older tank-
ers and bulk carriers. The methods
used so far have been based on the
principle of visual inspection by com-
petent experts, supported by thick-
ness measurements. The selection
of the areas of the ship to be sur-
veyed and measured has, to a large
extent, been concentrated on sus-
pected weak spots, and has depended
on the experience of the surveyor. It
has not been possible to predict and
localize these areas with precision.
The difficulty has been exacerbated
by the extremely tight schedules
under which the surveyors have to
work.
The result has been that deci-
sions affecting the current and fu-
ture safety of ships have been made
under far from ideal circumstances.
This was of less importance in ear-
lier times when ships were smaller
and of considerably higher residual
strength, but is not satisfactory for
the older, larger vessels now at risk.
GL has begun to break new
ground by bringing sophisticated
computer and laser measurement
technology to bear on the problem.
This is being supported by pressure
tests to determine deformation of
bulkheads and outer plating under
load, and by measuring and analyz-
ing the natural vibration of the ves-
sel. These calculations should pro-
vide a much more scientific basis for
the surveyor before commencing a
visual survey.
All this enables a visual display
computer model to be built up (see
Figure 2) showing all of the struc-
tural components of the ship with
their permissible corrosion allow-
ances. From the thickness mea-
surements of many investigations
by GL surveyors throughout the
world, the critical areas are deter-
mined in relation to the ship type,
and are incorporated into the model.
In this way, a forecast can be made
of the structural strengthening that
may become necessary at a later
stage, or the operation limitations
that may have to be imposed on the
ship. It will also permit additional
strengthening calculations to be
made without any great additional
effort. We believe that these sophis-
ticated models will mean that the
existing procedures for classifying
the older, larger vessels, will change
soon, and that GL will once again
have made a significant contribu-
tion to safety at sea.
October, 1993
Consilium Marine Offers
Range Of Safety Products
Consilium Marine develops and
manufactures marine equipment
and instrumentation under the trade
names SAL, Neptumatic, Gunclean
and Salwico. The equipment is sold
worldwide in large numbers to all
types of vessels, to shipyards, to
owners and to navies. The company
has subsidiaries in Germany, U.K.,
U.S., Japan, Korea and China, as
well as agents and representatives
in more than 40 countries. The
Consilium Marine product range
includes: SAL speed logs; Salwico
fire alarm systems and gas alarm
systems; Gunclean tank cleaning
systems; and Neptumatic waste
water and sewage treatment plants.
For additional information on
Consilium Marine products,
Circle 66 on Reader Service Card
International SOS Assistance
Launches Maritime Services
SOS Maritime Services provides
direct medical advice by physicians
24 hours a day, 365 days a year,
using all modes of communications,
including telephone, telex, satellite
and radio. In addition, SOS Mari-
time Services provides: a 24-hour
(Continued on page 44)
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